Apparatus for producing mixtures of air and pulverulent materials



1942- M. P. cH PLm 2,303,821

PRODUCING MIXTURES OF AIR AND PULVERULENT MATERIALS Filed ,Aug. 23, 1959 2 Sheets-Sheet 1 APPARATUS .FOR

Inventor,

Dec. 1, 1942. v M..P. CHAPLIN' 2,303,321 APPARATUS FOR PRODUCING MIXTURES OF AIR AND PULVERULEIT MATERIALS Filed Au 23, 19 s) 2 Sheets-Sixeei2 as l Z L M 'IIIIIIII Q Ill/II. z I

A I Inventor,

Patented Dec. 1, 1942 APPARATUS FOR PR OF AIR 'AND PULVE or to Chaplin Corporation, corporation of Maine onucrue. MIXTURES RULENT MATERIALS Merle P. Chaplin, South Portland, Maine, assign- Portland, Maine, a

Application August 23, 1939, Serial No. 291,626v

4 Claims. (01. sea-5s) Freshly printed sheets of paper or like material frequently require that they bepiled or stacked immediately after the printing operation. When so piled or stacked, considerable weight or pressure is placed on the freshly printed sheet by those sheets stackedv above it, particularly near the lower portion of the pile or stack. This weight or pressure is sometimes sufficient to cause a transfer of some of the ink from a freshly printed sheet to the surface of the sheet laid on or against it. This is known in printing parlance as offset and is, of course, objectionable from every standpoint.'

One very essential factor in the application of materials to a freshly printed sheet is the preparation of the medium to be applied to the sheet, so that a uniform, predetermined and evenly distributed quantity can be applied to the sheet surface.

Due to the objectionable feature of mixing liquid with the material many attempts have, therefore, beenmade teria1 directly to the sheet surfacewithout using a liquid vehicle as a conveying means. Such attempts have in the past onlybeen partially successful due very considerably to the improper or incomplete preparation of the materialbefore it is delivered or projected on the sheet. The projection of material, without aliquid conveying vehicle is usually accomplished by a jet of air, the oflsetx eliminating material being mixed with this air in a predetermined and controllable quantity. For any effective use-of this method,

the material must be mixed very uniformly with the air at all times, and as only a very minute quantity of certain materials are necessary for offset elimination if properly deposited on the sheet, and'the problem of mixing these most emcient materials with air, uniformly and in controllable amount, has been one which has not heretofore been satisfactorily solved.

My invention herein described provides an apparatus for, and method of mixing various offset elimination materials with air in any predetermined quantity, or ratio of material and air, of imuring that all material delivered with the air is properly prepared and of proper and suitable particle size, and of maintaining a proper ratio of material and air under all conditions, so long as the apparatus is supplied with proper materials in bulk form. The materials ordinarily used may include many finely divided or powdered materials such as talc, French chalk, soapstone, China clay barium, aluminamalcium, magto apply some suitable ma- 2-4, Fig. 1;

Fig. 6, cross section through connecting rod on some of these being used in the form of carbonates, oxides, sulphides, or hydrates, individually or in combination. In my apparatus, bulk materials are introduced into the lower section of. a suitable container, these materials are properly broken up by mechanical agitation, a portion of the material which has been divided or brokenup is separated from the coarser material and transferred to the upper section of the container, it is again treated to remove any coarse or lumpy-material and mixed with a predetermined and controlled quantity-of air, after which it may be withdrawn or discharged to or on printed sheets for offset elimination purposea.

Reference is made to the following figures:

Fig. 1, sectional elevation through container agitator and air control valves, taken on line l-l, Fig. 2; I i

Fig. 1 is a section showing the valve in a different position;' a I Fig. 2, plan view of container viewed from line Fig.- 3, sectional elevation through lower portion of container, with agitator raised;

Fig. 4, sectional plan viewthrough container and agitator on line4-4, Fig. 1;

Fig. 5, power operating means and section;

through agitator level control chamber;

line 66, Fig. 5;

Fig. 7, cross section through agitator levelcontrol chamber with container having maximum supply of bulk dust material;-

*Fig. 8, section through agitator level control chamber when chamber has .minimumsupply of bulkdust material. 1

My apparatus consists of a bottom container section I and a top container section 2'which are secured together by means of flanges 3. 'I'hese'sections form a closedtank or-chamber in which the bulk material S is mixed with air in proper ratio or relative proportion as desired and controlled by the operator.

The material in bulkform is introduced through filler plug opening-4,.passin'g downward through the tank section Linternahcone section 5, down over the outside of agitator :6 to the bottom portion of the tankas 'shownc-at and a vertical nesium, titanium, silicates, starches, zinc, etc., as

' The agitator 6 COIlSiSlJS'DfQ; conical portion 1 flange .portio'n 8, .and somewhat above the lower edge of this flange .is; stretched tator 6-=is moved up and down in a vertical direction by rod l0, said rod being secured to agitator 6 by any suitable means such as a threaded 1 portion on the end of rod Ill, and nuts ll. Agi- 2| to which is secured a piston 22,'the top of cylinder 20 being closed by cap 23 with packing and packing gland 24 providing an oil tight seal for the rod 2|. The piston 22 is provided with holes or passages 26 with a valve 25 overlying these holes or passages on the top of the piston permitting the fluid in the cylinder to pass up through the holes from the bottom of the-piston to the top, but preventing the oil or other liquid from passing downward through these holes 26 to the bottom part of the cylinder or below the piston.

The piston 22 is moved up and down by r'od 2| operated by means of lever 21 pivoted'at 2-8 in.mounting bracket 29, and connected at one end by pin 3|l with piston rod 2|. end of lever 21 is moved or oscillated by means .of a motor or other suitable mechanism 3|, op-

erating through a crank 32, crank pin 33 and connecting rod 34 attached by means of pin 35 to lever 21. Lever 21 may be slotted, as indicated at 36, so that the relative angular oscillation or movement of lever 21, and the resulting vertical motion of pin 30, rod 2| and piston 22 may be varied. Motor 3| is secured to the top of container section 2 by mounting bracket 31.

It will thus be seen that the operation of motor 3| will cause the lever 2| -to oscillate which, in turn, causes the vertical reciprocation of agitator 6 in the bottom of the container through the fluid connecting medium F contained in cylinder 29 as will be hereinafter described in greater detail.

Air is supplied to the container. sections l and 2 through a control and pressure regulating valve 38, the air passing through this valve in the direction of the arrows to a distributing valve 39. In Fig.1, the air from the pressure regulating valve 39 enters the hollow central portion ll of adjustable plug 40, passing outwardly therefrom through opening 42. In the plug position shown in Fig. 1, the air, passing through opening 32 is equally divided in space 35, passing in the direction of the'arrows to openings 43 and-M in the outer section of valve 39, the air from opening '43 being connected by suitable piping to air inlet IS in container section 2, and from opening 44 by suitable piping-to inlet IS in container section 2. Air may be so introduced as to maintain the container interior under substantial pressure.

In Fig. 1a illustrating another position of valve 39, the adjustable plug portion 40 has been moved in such a manner that the opening 43 isclosed so that no air can pass from the valve 4|! to the container inlet pipe It All of the air, therefore, passes thru valve'opening 44 to container pipe I! as shown by the arrows.

It is obvious that any intermediate adjustment I of plug section All in valve 39 will enable the proportion of air supplied from the pressure regulating valve 33, to be divided between container inlet pipes l5 and |'6 in any desired proportion orratio, from all of the air being supplied to to the container through The opposite pipe I! with no air being supplied to pipe It or a condition just the reverse.

The inlet pipe l5 enters the container section 2 at a somewhat lower level or elevation than pipe 16. Between these elevations is interposed an inverted open-end cone member 5, the opening 5a being in its downwardly projecting apex, and providing an open connection between the thusly divided container sections 36 and 41. The inverted cone 5 is secured about its periphery to the wall of containersection 2 so as to make an air-tight joint.

Assume that bulk material has b n supplied filler plug and has found its way as previously described into the bottom section of the container as shown at 8., Assuming that it is now desired to secure a supply of finely divided powdered material mixed with air for deposition on a freshly printed sheet,

7 the motor 3| is placed in operation which in turn causes a vertical reciprocation of rod Ill and agitator 6. The agitator 6 alternately takes a position as illustrated in Fig. l periodically being raised to a position as illustrated in Fig. 3 so that the projecting flange 8 is raised above the level of material S in the bottom of the container.

When the agitator 6 again moves downward its vertical edge or rim 8 encounters the surface of the bulk material S entering it for a short distance, and as it enters, the air trapped in the interior or cone portion 1 is blown downwardly, outwardly and upwardly as indicated. by'the arrows, thereby projecting a cloud of the bulk material mixed with air upwardly into zone 46. This operation is periodically repeated with the result that the space or zone 49 becomes charged with pulverized and finely divided bulk material, discharged into and maintained in zone 46 by the mechanical action of member 8.

The coarse screen section 9 which is stretched across the vertical section 3 somewhat above its lower edge prevents the bulb material from build ing up in cone shape inside. ofthe agitator 6, the mesh of this screen being so proportioned that it will flatten out the bulkmaterial on 'each downward stroke, but is sumciently coarse so that none of the bulk material will be lifted by it on an upward stroke.

After the agitator has been in operation for a brief interval, zone 43, as has been previously described, will havebeen charged with bulk material, the more finely pulverized or divided materials remaining suspended in the air, and the heavier materials falling downwardly over the outside of the conesection 1 and back onto the surface of the bulk material where they may be again agitated, reduced in size andproiected upwardly.

in the upper view, air will be admitted in equal proportions through inlet pipes I3 and I3 to the interior of container 2. The air which enters the container through pipe It cannot escape downwardly, therefore passes upwardly through opening 5a in' the inverted cone 5 or from zone ll .nto zone 41 in the direction indicated by the arrows.

. It will'be noted that both pipes l5 and I9 enter the tank tangentially, resulting in a'fwhirling or spinning action cum: air inside of the container 2, which will further segregate the finely divided bulk materials from the coarser particles, the coarser particles falling downwardly along the wall of container section 2 back to the surface of the bulk material, while the finer materials are carried towards the center of the container, and pass upwardly from zone 46 to I zone 41.

Air is also entering container section 2 through pipe I6, and entering the tank at 'an angle induces a circular or spinning motion in the same direction as given the air in zone46. Any coarse particles or lumps will therefore be carried" outwardly to the container wall and drop down this wall and down the inclined wall of cone 5, and back to the agitator for retreatment. This air entering container section 2.through pipe I6 is at the same pressure as regulated by valve 38 as the air entering pipe I5 into zone 46, therefore, the air entering zone 41 through pipe: I6; c'annot escape downwardly through opening 5d ininvertedcone 5 and therefore builds up a pressure in container section.2 corresponding to the regulation of valve 38 or escapes through outlet pipe 48 at or near the top of container section 2. The

outlet pipe 48 may be connected to any suitable distribution or application means for applying or distributing the finely divided material contained in the air on or to the freshly printed sheet orother material which it is desired to protect against printing offset. This distribution or applicaton'means forms no part of the present invention.

Under the conditions just described, the agitator 6 will continue to charge zone 46 with pulverized bulk materialand air, entering zone 46 through pipe I5 will assist in the segregation of the fines from the coarse, and discharge the fine particles upwardly through opening 5a into zone 41. If a very considerable quantity of air enters zone 46 through pipe I5 a corresponding considerable quantity of finely pulverized material will be transferred from zone 46 to zone 41.

If, on the other hand, a lesser quantity of air is supplied through pipe I5 to zone 46 a corresponding lesser quantity of finely divided pulverized material will be transferred from zone 46 to zone 41.

Assuming that a certain quantity of air in which is mixed the finely divided materials, is to be dischargedflfrom outlet pipe 48 this being regulated by the operator by pressure control valve '38, it is obvious that the air leaving the tank through outlet pipe 48 must enter the tank either through pipe I5 or I6 or through them jointly in some ratio of air quantity. Distribut ing valve 39, being interposed between the supply and pressure regulating valve 38 and container 2, permits the quantity of air entering container 2 to be divided in any desired ratio or proportion between pipes I5 and I6, or to zones- 46 and 41. If the .valve 38 is adjusted as shown in the lower view, no air being allowed to enter zone 46 through pipe I5, all of the air escaping through outlet pipe 48 will find its way into container section 2 through pipe I6 and zone 41. r-Under this condition, there will be no air flowing into zone 46 and consequently no air passing upwardly through opening 5a into zone 41 and consequently no finely divided bulk material being transferred from zone 46 into zone 41.

The motion of the agitator 6 while maintaining a charged condition of air and pulverized material in zone 46, does not, however, cause any transfer of air or material from zone 46 to zone 41 as no circulation between these areas can be established by the motion of agitator. 6 and consequently no transfer of material from one zone to the other. Under these conditions, substantially clear air would be discharged from outlet pipe 48, as zone 41 would be supplied only with clean air through pipe I6. However, if the adjusting member 48 of valve 39 is moved so that a small quantity of air is admitted to pipeI5. while still admitting the major portion of the air necessary through pipe I6 a small quantity of finely divided material will of necessity be transferred, as previously described, from zone 46 to zone 41 hich quantity of air will be supplied with the g eater quantity of air supplied through pipe I6 both escaping through outlet pipe 48. If the adjustment of valve 39 is such that all of the air through supply and regulating valve 38 is admitted to container section 2 through pipe IS, the concentration of finely divided materials in zone 41 will speedily become the same as in the central portion or zone 46, and a greater ratio of material with air will be discharged from pipe 48.

Many previous attempts have been made to pulverize the bulk material andmix it with air by means of an air jet, either projected downwardly against the surface of the bulk material or upwardly through the material itself. Either method of air application for breaking up the bulk material is unsatisfactory and insuflicient as the bulk material may at times break up rather easily, resulting in the air picking up and carrying with it a great quantity of the material, or at other times, the material may resist the action of the air blown on its surface, or build a channel up through the material from a bottom inlet to the top of thematerial so that a very much less quantity of this material is picked up and carried away by the air current. Similarly,' if more or less air, or air at greater or less pressure is supplied, this will immediately change the amount of materials picked up and carried away. Such variations are not permissible, as they result in either too little or too much material being present in the air or which may be distributed .over a sheet, and such variations are out of control of the operator and no means is available to him for making any permanent correction, as conditions within the tank may change even as he may change some exterior adjustment, thereby. upsetting and nullifying anything which the operator did or can do. Such an arrangement for supplying air containing minute particles for offset elimination, is, therefore, entirely inadequate and useless.

However, employing a mechanical agitator which mechanically contacts and breaks-up the surface of the bulk material, at the same time projecting this material upwardly into a section of a' container tank, automatically provides a substantially and consequently uniform charge of mixture of pulverized materials and air which and thereby provide a uniform'constantly maintained ratio and mixture of air and material. Ofiset elimination on lightly printed sheets requires only a small quantity of very finely divided materials. Heavier printed sheets will require more .material, and it may ,well be of somewhat "coarser texture and-the particles larger to effect a greater sheet separation. My apparatus auto-- matically provides this desirable condition, as when only small quantities of material are required, the mechanical agitator has more time to pulverize the materials, and make them finer. when greater quantities are required, the agitator has less time to pulverize the material, and the greater quantity of air entering zone 46 through pipe l5 will be capable of transferrin material having larger particle size from zone 46 to zone 41 than when a lesser quantity of air is admitted through pipe l5 by means of valve Mention has been made of a slotted portion '36 of lever 21 which provides for adjustirr the amount of vertical travel of agitator 6. This permits of adjustment of the mechanical impact 'and agitating effect of agitator 6 on the bulk material by giving a greater or lesser impact on the material, thereby effecting a greater or lesser degree of pulverizing or breaking up action and a I greater or lesser degree of projecting this broken-up material into an area or space where it can be utilized. It is also possible to adjust the speed'of motor 3| by any well-known means (not shown) so that the period or rate of impact of agitator 6 on bulk material can be changed, thereby providing the operator with a means of utilizing a wide range of bulk materials S as may be best suited to the particular problems of offset elimination with which he is faced. Assuming the operator has adjusted either the speed of the motor 3| or the vertical motion of agitator 6, or both, to provide for the most satis-- factory operation on the bulk material which he may-then be using, he. then has available two additional adjusting means for determining the rate at which this material may be utilized, and also the amount of material which may be projected or taken from the container for application to the sheet.

This supply and regulating valve 38 provides a ready means for adjusting the amount of air-suppliedto the container-section 2 which in turn determines the amount delivered from pipe 48 and which in turn enables the operator to control the distance and degree of the distribution of the materlal. In addition, the distributing valve 39 provides the operator with a ready and \easy means of adjusting the amount of air supplied to the heavy particle zone 46 and the light particle zone 41, so that the desired quantity of material, and only the desired quantity, is'transferred'from zone 46into zone 41, being thereafter discharged from zone 41 through pipe 48.. It has already been mentioned that the bulk materials are furnished to this apparatus thru filler plug 4, and are deposited or stored in the bottom of container section I as indicated at S. It is desirable that sufiicient storage space be provided so that the apparatus can be supplied with these bulk materials in sufflcient quantity so that they will not need frequent replenishment. It is obvious, of course, that bulk materials being in a compact mass do not require as large storage space, as when and broken up and properly mixed with air in the small'quantity necessary for offset elimination; hence a small quantity from a bulk standpoint will produce a very large quantity of air mixture.

- This bulk material being stored in the bottom of container section I has a natural tendency to settle into a. fairly compac body, which further enables more material to xe stored for use.

The mechanical agitator 6 h ever, breaks up this compact mass into finely divided particles as has-heretofore been described and discharges they are pulverized these partic I es into zone 46 where they are picked up by the controlled and regulated air currents. The vertical rim 8 on the bottom of the agitator 6 acts as a pulverizing and breaking member on the bulk material, the coarse screen section 9 stretched across the agitator 6 prevents the material from building, up inside the agitator, and

further acts to pulverize the center surface ,area

of the bulk material, and the discharge of air from the center cone-shapedarea of the agitator ejects this pulverized material dicated by the arrows.

It is obvious, of course, rial is pulverized, mixed with air, through outlet pipe 48, that the surface line will gradually be lowered as the material is used up. In order to insure that the flange or rim 8 of the agitator 6 always encounters or impacts the surface of the bulk material in the same manner regardless of the amount of material in com tainer section I, the cylinder 20 together with the associated parts illustrated in Figs. 5, '1 and that as the bulk mate- 8, is provided. The cylinder 20 is filled nearly,

' is not resting or held by its contact'with the surface of the bulk material S in container section I.

The normal weight ofthe agitator 6 together with rod l0 and cylinder 20' is suflicient to overcome any friction of the rod 10 in the agitator d move downwardly unless always tending to travel or it is prevented from so doing by its contact with the bulk 'material S. 1

Howeven with the motor 3| operating at normal speed, the lever 21 oscillates sufliciently rapidly so that in its upward motion, and carrying with it rod- 2| and piston 22, the cylinder 20 is lifted almost as great a distance vertically as the travel of the piston 22, there being however, a slight leakage by the piston and consequently a slightly less travel upward imparted to cylinder 20. On a return or downward stroke of rod 2| the piston 22 and cylinder 20 move downwardly in substantial unison until the flange-8 of agitator 6 encounters the surface of the bulk material S in the bottom of the impact has occurred the bulk material as of the agitator and its associated parts, any continued downward travel of the piston 22 will impart no added impact or pressure on the bulk material, as the oil or other liquid F in the lower section of cylinder 20 will escape --upwardly as indicated by the arrows, through holes 26,- lifting valve 25 and'passing into the area or space above the piston. Immediately the piston-starts back upward again, the valve 25 closes to insure that the cylinder and agitator be again lifted its predetermined and regulated amount as controlled by the position of pin in slot 36 of lever 21.

Fig. 7 illustrates the relative position of the piston and cylinder in both its upward and downward strokes-when the container section I has been freshly filled with bulk material to practically its entire capacity. The partial sections of container. After suflicient rbetween the agitator and the Fig. '7 indicate schematically the amount of upwardly as in'- and delivered in' passing through the guide [2 or the packing l3 resulting,

determined by the weight) thepiston is traveling upward. Fig. 8 shows the 1 relative position of the cylinder 20 in its downward position, and the space of travelN shown between-the cylinder positions of 1 and 8 shows the normal amount of liftof the cylinder by the piston. It is obvious that the amount of liquid which is bypassed around the piston, can be readily controlled or adjusted by increasing or decreasing the space between the piston and cylinder, or by using a lighter or heavier liquid in the cylinder. While the bypassing or leakage of the liquid around the piston or between it and the cylinder has been described only asapplying to the upward stroke of the piston, there may also be a slight leakage on the downward stroke of the piston, as the cylinder may tend to move faster than the piston on the downward stroke as well as slower than the piston on the upward stroke. In any case, this downward motion or slippage of the cylinder accomplishes the same result with the assurance and certainty that the agitators will always contact and impact the surface of the bulk material S in the bottom of the container.

As this bulk material is used-up and discharged from the container, thenormal relative positions of the piston 22 and cylinder willchange from that indicated in Fig. 7 to that indicated in adjustment feature is so arranged that it acts as an aid to one or more of the others.

For instance, incase of a lightlyv printed sheet,

and where little ofiset eliminating material is still enable him to use aconsiderable quantity of air through both ,pipes I5 and I6, to perhaps effect betterdistribution over a large sheet. For an extremely heavily inked sheet, the operator may do just the opposite. Or he may be using aninkon which he wishes to use only the minimum of necessary material. Or the sheet may require a second printing, in which case too much, or unnecessary. use or excess of material is objectionable. The operator not onlyhas a simple method of controlling quantity of material, but also its fineness or particle size, and this without the necessity of changing the material in the container, or stopping the --apparatus.

The method of preparation permits the use of a wide range of materials, or combinations of materials. Some very desirable materials may have a tendency to lump or pack under varying atmospheric conditions, and therefore not be usable with equipment heretofore available. The provision of a mechanical agitator, with variable speed and degree of impact, enables the use of ma- 8, in which condition the container will be nearly empty, and there will have been discharged through the outlet pipe 48 all of the bulk materials storcd in the bottom of the container. The storage space for bulk material may be of any desired depth as determined by the length of the cylinder 20 and the relative piston positions Fig.

7 and Fig. 8. v

It will, therefore, be observed that under all conditions the agitator B operates in exactly the same manner on the bulk material regardless of whether the tank has been freshly filled or is nearly empty, and there is no difierence in the amount or degree of pulverized materials delivered to zone 46 whether the storage of bulk material S be at the maximum container capacity or its minimum capacity.

It will thus be seen that I have provided a novel yet simple apparatus for and method of preparing bulk materials to be used for printing ofis et elimination. are necessary. Any suitable material, or combination of materials in dry-bulk forin can be used. These materials are definitel and positively broken up and pulverized in the finely divided state necessary for use in complete and efficient offset elimination. In suph a finely divided state, the material has no detrimentalefiect on the printed surface, and my apparatus and method of material preparation and delivery, prevents anything but material of the proper size and fineness from being delivered for use.

Ample storage space for the bulk'materialsis provided. The apparatus can be operated for long periods of time without stopping to add fresh material. During the use of this large amount of material, there can be no change in the quality or quantity ratio of. material delivered with any one setting or adjustment of the apparatus. Adequate adjustments are provided so that the operator can meet and eliminate any ofiset condition in the most efiicient manner. These adjustments are not inter-dependent, nor

No messy liquid conveying agents in said container.

terials ordinarily diflicult or impossible to handle. Double separation of fines from coarse or lumpy masses insures delivery of only properly prepared material. Control valves for quantity and distribution with dual mixing of the air with thematerial before it leaves the container, insures evenness and uniformity of mixture, uniformity of particle size, and ready' and simple adjustments ofboth' air quantity and ratio ofair and material.

In describing my method of preparing materials for offset elimination, I have shown a specification apparatus arrangement. I do not limit myself, however, to this specific design or ar- V rangement of mechanical parts, other than asset forth and within the scope of the accompanying claims. g Having described my invention, what I claim is:

1. Apparatus of the class described, comprising a closed container, an agitating member for pulverizing and agitating material stored in said container, means for operating said agitating member, and means cooperating with said first mentioned means whereby the position of said. agitating member is adjustedyvertically relative to the material stored in said container, to effect constant and vequal pulverizing and agitating ac-' tion regardless of the amount of material stored 2. Apparatus of the class described,"comprising a container divided into two zones by a partition having an .opening' therein, a mechanical agitator for pulverizingsaid bulk material in said lower zone, and for mixing said. pulverized material with air, anair jet admitting air to said lower zone efiecting a segregation of'the finely pulverized material and the discharge of this material 7 with air-into the upper zone, and a second air jet does one react against another. Rather, each admitting air to .said upper zone to efiect a further segregation of finely pulverized materials and the discharge of said finely pulverized material with air from said second zone and from said container. v

3. Apparatus of the class described, comprising a closed container, a partition said container with walls sloping towards a central opening, and separating said container into upper and required, the operator may reduce the agitator speed, or its .motion, or both, thereby creating *a lesser concentration of material in zone 46 and material contained lower zones, a mechanical agitator and pulverizing member operating topulverize and agitate tainer, an air pipe connected to said container adjacent to said agitator in the lower zone, a second air pipe connected to said container in the upper zone, and means to admit air to said container through said pipes, and to control the relative amount of airadmitted through each of said Pipes.

4. Apparatus comprising a closed container in-th lower zone of said conpermit passage of the amount of air admitted to each container zone.

P. CHAPLIN. 

